1. Field of the Invention
The present invention relates to an alternator for motor vehicles or the like, and a manufacturing method thereof. More particularly, the present invention is related to a mounting structure in the alternator for mounting the alternator to an engine and a manufacturing method thereof.
2. Description of the Related Art
Generally, in a conventional method for mounting an alternator to an engine of a motor vehicle, as the engine vibrates, this vibration is directed to the moving direction of pistons, i.e. to the alternator. As a result, the level of radial vibration is high. Further, in a multicylinder engine, because of a phase difference in the vertical motion of each piston, an axial vibration of the rotary shaft of the alternator can occur. Furthermore, a high engine speed can cause a strong vibration since the vibration level is directly proportional to the speed of the engine.
To cope with these drawbacks, U.S. Pat. No. 4,849,665 (the Japanese Utility Model Publication No.Hei 5-40686) discloses a mounting structure for mounting a bracket's flange by clamping it in a direction which is perpendicular to an axial direction of a rotary shaft of an alternator.
On the other hand, U.S. Pat. No. 4,945,272 (the Japanese Utility Model Publication No. Hei 6-6688) discloses a flange having a U-groove formed in a direction which is perpendicular to an axial direction of front and rear brackets, respectively. The flange is secured by a mounting bolt via screw-engagement. It is described in this patent that, for each mounting boss, an opening of the U-groove may be formed in one direction instead of alternately in the opposite direction. It is also described therein that the U-groove may be formed with its opening directed either leftward or downward.
In this field of art, there is a long felt need to use a structure which is strong and vibration resistant, has fewer machining steps for the entire housing, and is free from a manufacturing defect while providing mounting holes and positioning holes.